THE  SEPARATION  AND  IDENTIFICATION  OF 
ACIDS  IN  LOW  TEMPERATURE  TAR 

BY 

DELLA  DARLE  JUNKIN 
B.  A.  University  of  Michigan 


1912 


THESIS 


Submitted  in  Partial  Fulfillment  of  the  Requirements  for  the 

Degree  of 


MASTER  OF  SCIENCE 

IN 

CHEMISTRY 


IN 


THE  GRADUATE  SCHOOL 

OF  THE 

UNIVERSITY  OF  ILLINOIS 


1921 


Digitized  by  the  Internet  Archive 
in  2015 


https://archive.org/details/separationidentiOOjunk 


UNIVERSITY  OF  ILLINOIS 


THE  GRADUATE  SCHOOL 


June  2 192.1- 


I HEREBY  RECOMMEND  THAT  THE  THESIS  PREPARED  UNDER  MY 
SUPERVISION  BY JQella.Darle  Junitin 

ENTITLED The  Separation  and  Ident.i  finn.t.i  on  of  Acids 

in  Low  Temperature  Tar. 

BE  ACCEPTED  AS  FULFILLING  THIS  PART  OF  THE  REQUIREMENTS  FOR 
THE  DEGREE  OF  _ 


I n Charge  of  Thesis 


Head  of  Department 


Recommendation  concurred  in* 


Committee 


on 


Final  Examination* 


*Required  for  doctor’s  degree  but  not  for  master’; 


i 


' 


TABLE  OF  CONTENTS 


Acknowledgment  Page 

I,  Introduction  1 

Purpose  of  investigation  1 

Historical  2 

II*  Experimental 

1,  Fractionation  of  tar  ^ 

a.  Extraction  and  purification  of  acids  6 

b.  Fractionation  of  acids  7 

c.  Physical  nature  of  acids  10 

2.  Extraction  of  acids  without 

fractionation  10 

a.  Dehydration  of  acids  11 

b.  Effect  of  steam  distillation  11 

c*  Effect  of  vacuum  distillation  11 

d.  Use  of  solvents  11 

e.  Choice  of  fractional  extraction 

solvent  12 

f.  Choice  of  precipitation  solvent  12 

g;  Purification  of  solid  acids  13 

3.  Tests  to  determine  nature  of  acids  14 

III.  Summary  and  Conclusion  20 

IV.  Bibliography  21 


. 

, 

. 

. 


. 


ACKNOWLEDGMENT 

This  investigation  was  carried  out  in  the  Chemical 
Laboratory  of  the  University  of  Illinois  1920-21  under 
the  direction  of  Dr.  Layng.  The  writer  takes  this  opport- 
unity to  express  appreciation  for  the  assistance  given  by 
various  numbers  of  the  department,  but  more  especially  to 
Dr.  Layng  for  his  cooperation  and  timely  assistance  which 
has  meant  so  much  to  the  progress  and  development  of  this 
work. 


. 


THE  SEPARATION  AND  IDENTIFICATION  OF  ACIDS 


IN  LOW  TEMPERATURE  TARS. 

I,  Introduction 

The  purpose  of  this  investigation  is  to  secure,  if 
possible,  the  acids  in  low  temperature  tar  in  their  original 
form  or  as  nearly  so  as  possible,  and  thereby  gain  some 
knowledge  of  the  mature  of  the  constituents  of  the  tar  and 
perhaps  of  the  original  coal.  In  the  process  of  low  temper- 
ature carbonization,  there  is  some  decomposition  of  the 
higher  boiling  consti tuents , but  the  amount  of  this  is 
small  in  comparison  to  that  produced  by  high  temperatures. 
Because  of  this  there  should  be  found  in  tar  some  of  the 
constituents  of  the  coal  not  wholly  decomposed  among  which 
many  acids  undoubtably  occur.  The  percentage  of  these  acidic 
bodies  known  to  be  high  in  low  temperature  tar,  their  separ- 
ation and  identification  may  give  some  idea  of  the  nature  of 
those  compounds  which  decompose  on  application  of  heat  to 
give  bodies  having  lower  boiling  points  and  some  which  later 
polymerize  to  give  the  higher  boiling  liquids  and  solids  in 
tar. 

By  the  low  temperature  carbonization^^  is  meant  the 

maintenance  of  such  temperature  that  the  formation  of 

naphthalene  and  fuel  oils  is  not  begun,  as  a result  of  the 

decomposition  of  the  higher  boiling  substances, 

( 2) 

This  transition  temperature v ' occurs  between  530  de- 
grees and  560  degrees  but  by  careful  distillation  a very 
slight  decomposition  can  be  made  to  occur  which  increases 


. 

* 


* 


' 


-2- 


with  rapid,  rise  in  temperature  resulting  in  a thickening 

(3) 

which  Schneider'  ' attributed  to  be  due  to  polymerization! 
and  thus  was  he  able  to  conclude  from  his  work  that  the  high 
boiling  substances  passed  off  undecomposed ^ 4 ^ from  the  coal 
in  the  coking  process. 

Professor  Parr  (5)  says  that  this  secondary  decomposition 
must  be  prevented,  and  may  be,  by  maintaining  a temperature 
of  less  than  750  degrees,  otherwise  the  "oxygenated  constitu- 
ents of  the  coal"  will  react  with  the  phenol  soluble  substances 
whicn  form  the  binder  for  the  coke, 

(6) 

Already  there  have  been  found  over  three  hundred 
substances  in  tar,  of  which  about  one  hundred  fifty  have  been 
estimated  and  over  ninety  separated  and  purified.  Among  these 
are.  neutral  basic,  and  acidic  classes,  containing  oxygen, 
nitrogen,  or  sulphur,  either  in  the  ring  or  in  the  side  chain 
and  comprising  five  and  six  membered  rings  exemplied  by 
benzene,  phenol,  pyridine,  thiophen,  and  coumarone.  Of  all 
compounds  contained,  tar  yields  but  few  in  large  quantities, 

such  as  benzene,  phenol,  and  naphthalene. 

(7) 

The  higher  homologues  of  phenol  occur  in  large 
quantities  in  low  temperature  tar  both  as  polyhydric  phenol 
and  their  esters  which  form  resins.  The  latter  remaining 
undistilled  if  a fractionation  is  made  at  240  degrees  and  form 
a perfect  material  for  road  making. 

Various  methods  have  been  employed  for  the  purification 
of  the  constituents  v ' of  tar  among  which  are  the  formation 
of  salts  of  organic  and  inorganic  reagents,  with  their  sub- 


■ 

. 


' 


- 

•'■i  ‘<n£^L 

- 


. 


-3' 


sequent  decomposition,  and  the  use  of  organic  solvents* 

( 9 ) 

Maclaurin  removes  bases  by  K2S04  , acids  by  NaOH , 

and  the  resins  by  means  of  hydrocarbon  oils. 

In  the  ordinary  method  of  separation  of  tar  acids,  an 

aqueous  solution  of  sodium  hydroxide  is  employed,  resulting 
in  a water  soluble  salt  of  the  acid  which  may  be  liberated  on 

addition  of  sulphuric  acid.  If  the  specific  gravity  of  the 
alkaline  solution  be  increased,  in  each  successive  extraction, 
afract.ional  separation  results,  v/ith  phenol  and  the  lower 
boiling  horaologues  appearing  in  the  first  extract. 

The  percent  of  acids  in  low  temperature  tar  is  high, 

(fifty  percent  a maximum)  but  shows  a great  variation  with 

different  tars , ( ^ ) because  different  coals  produce  different 
types  of  tars;  the  younger  the  coal,  the  greater  the  yield  of 

acids,  in  any  given  tar.^-1,c^ 

When  however,  the  acids  are  removed  from  low  temperature 
tar  there  remain  behind  hydrocarbons  which  are  not  character- 
istic of  any  definite  tar,  in  decided  contrast  to  tars  produced 
at  high  temperatures.  These  residues resemble  more 

closely  petroleum  products. 

(14) 

Heating  of  these  petroleums  like  paraffin  hydrocarbons 
causes  decomposition  followed  by  polymerization  to  substances 
of  aromatic  nature. 

Identification  of  phenol  and  its  homologues  has  consisted 
(15) 

of  color  reactions  and  the  formation  of  derivatives  • 

hot  the  least  among  these  derivatives  is  the  condensation 
with  formaldehyde  or  with  hexame thylene  tetramine  giving 


■ 


■ 


* 

. 


-4- 

-d  *1  n ^ 4.  (17)  -r,  , n (18).  Dr.  Baekeland  defines  a 

Baekelitev  ' or  Reamanol  v 

"phenolic  tody"  as  one  having  & benzene  neucleus  with  the 

hydroxyl  attached  to  the  ring  either  in  a free  or  substituted 

(19) 

form.  Moreover,  anhydrides  of  the  side  chain  hydroxyls 

will,  if  produced  by  very  careful  heating,  condense  to  give 
an  infusible  product  with  formaldehyde  but,  if  no  such  anhyd- 
ride be  present,  there  must  be  a substance  of  phenolic  nature* 
(21) 

Sage  has  observed  that  an  aqueous  solution  of  NaOK 

does  not  remove  all  of  the  acidic  substances  from  tar  and 

that  there  remains  behind  dissolved  in  the  sodium  phenolate 
and  higher  homologues  a large  percent  of  the  acids. 

These  insoluble  compounds  are  of  asphaltic  type  and 
( 22) 

Schneider  v ' has  reduced  the  percent  of  these  compounds 
by  heat  and  pressure  to  one  half  their  original  amount  and 

secured  a corresponding  increase  of  low  boiling  phenols. 

Marcus  son  ( 23)  found  ths-t  by  blowing  air  through  heated 
tar  there  were  produced  substances  which  were  asphaltic  in 
nature . 

To  these  substances  does  Hubbard  (24)  attribute  the 
superiority  of  low  temperature  tar  to  the  process  of  road 
building.  In  the  determination  of  the  percent  of  "soluble 
bitumen"  he  suggests  the  use  of  carbon  disulphide ( 25 ) and 
subsequent  precipitation  in  hydrocarbon  oil. 

Robertson^6)  finds  pyridine  a suitable  solvent  for  the 
extraction  of  resinic  and  cellulosic  bodies  from  low  temper- 
ature tar. 


-5- 


Me thod  and  Manipulation 

The  method  of  securing  the  acids  as  nearly  like  those 
in  the  crude  tars  as  possible  was  two  fold  (a)  distilling  the 

tar  and  extracting  the  acids  and  their  subsequent  fractionation 
and  (b)  fractional  extraction  by  means  of  organic  solvents 

and  prec lotion  reagents. 

The  tar  was  dried  and  distilled  according  to  the  method 
suggested  by  Church.  (21?)  There  was  a very  large  amount  of 
foaming  due  to  the  high  pyridine  content  and  decreased  but 
little  until  the  last  traces  of  water  had  passed  over.  At 
a temperature  of  300  degrees  heavy  decomposition  occurred  and 
the  residue  in  the  still  began  to  increase  in  volume  and 
viscosity,  finally  resulting  in  a coke  that  was  porous  but 
hard  and  having  a volume  of  twice  that  of  the  residue  in  the 
still  at  the  beginning  of  heaviest  decomposition. 

TABLE  I. 


Crude  Tar  Frac  tionation 


f,H20 

.81 

.72 

% to  170 

13.2 

120 

% to  230 

25.9 

26.9 

( 

fo  to  320 

7.6 

8.1 

% to  360 

8.4 

9.2 

% pitch 

27.6 

25.4 

% decomposi- 

tion 

15.49 

17.68 

r 


-6- 

Each  fraction  as  above  made  was  treated  with  an  aqueous 

solution  of  sodium  hydroxide  and  the  hydrocarbon  removed  from 

the  alkaline  solution  by  means  of  steam  distillation.  The 
acids  were  then  liberated  by  the  addition  of  sulphuric  acid 

and  a second  steam  distillation  gave  a very  pure  acid. 

This  method  was  successful  for  all  low  boiling  phenols, 

but,  with  increase  in  boiling  points  the  amount  of  steam 

needed  to  distill  a given  Volume  of  acid  rapidly  increased. 

Moreover,  there  remained  in  the  still  at  the  end  of  purifi- 
cation of  the  270  degree  fraction  a black  viscous  mass  which 
could  not  be  distilled  with  steam. 

The  futility  of  this  met  nod  in  securing  the  high  boil- 
ing acids  v/as  avoided  in  the  highest  fraction  by  heating  the 
alkaline  solution  in  anopen  vessel  thus  removing  any  hydro- 
carbon and  then  neutralizing  "by  the  use  of  H^SO^  The 

resulting  phenols  were  darker  in  color  and  more  viscous  than 
those  secured  by  the  previous  method. 

A sample  of  the  acids  thus  purified  was  subjected  to  a 
time  temperature  distillation  with  a view  of  determining- 
points  for  fractionation.  The  results  of  this  process,  how- 
ever, snowed  no  marked  points  of  increase  in  volume  for  any 
set  temperature  and  the  amount  of  distillate  steadily  decrea.sed 
with  a rise  in  temperature.  The  distillate  at  first  was 

\ 

water-white  but  on  standing  assumed  honey  yellow  color.  The 
succeeding  distillates  increased  in  depth  of  color  and 
viscosity  and  difficulty  wa.s  encountered  toward  the  end  of 


'\I,}  - * ' 12  ' • 


’ 


* 

’ 


" 


-8- 


-9 


the  process  in  the  chokin  , of  the  condenser* 

Another  sample  of  the  purified  acids  subjected  to 

repeated  distillation  and  the  physical  nature  'and  yields 
noted  with  the  following  results: 


TABLE  IX 

Repeated  distillation  of  Pure  Acids 
Distillation  flo.  1 2 3 


of  Distillate 

to  170 

0 

0 

0 

'•50 

45.  6 

46.3 

60.3 

270 

23.1 

15.5 

11.7 

520 

6.1 

7.7 

7.4 

340 

4.6 

4.4 

2,2 

Prom  the  foregoing  data  the  amount  of  decomposition  in 
the  higher  boiling  fractions  gradually  increases  giving 
bodies  having  lower  boiling  point* 

The  higher  boiling  constituents  grew  darker  in  color 
with  each  successive  distillation  and  became  so  viscous  as 
to  be  poured  with  difficulty  after  several  such  heatings* 
(iluud^*^  has  sao ./n  that  if  the  high  boiling  tar 
acids  are  h ated,  their  decompostition  results  in  an  increase 
in  the  yielu  of  phenol  w iich  probable  explains  why  the  per- 
centage of  phenol  is  so  much  lower  in  the  tar  produced  by 
the  low  temperature  coking  process  than  that  of  ordinary  tars. 

(2i>) 

Fischer  elso  maintains  that  the  percent  of  phenols 


-10- 


can  "be  doubled  by  cracking  tars  at  high  temperatures. 

Having  found  no  satisfactory  temperature  for  taking 
fractions  the  cuts  were  made  at  those  temperatures  known  to 
be  about  the  boiling  points  of  several  substances  previously 
found  intars,  ie,  phenol  186  degrees,  cresols  200  degrees, 
xylenols  210  degrees  and  225  degrees. 

Color  tests  with  FeCl-z  were  made  on  these  members  and 

£ 

positive  results  were  secured  but  in  no  case  was  an  individual 
member  isolated. 

Comparative  tests  of  the  members  of  the  liquid  acids  were 
made  with  those  of  the  solid  acids  secured  by  the  second  method 
of  extraction.  This  consisted  in  treating  the  crude  tar  with 
a 50%  solution  of  potassium  hydroxide.  Successive  extractions 
with  the  alkali  finally  gave  an  aqueous  extract  that  contained 
but  a small  part  of  the  acids,  but  still  was  not  colored  on 
further  admixture  with  the  tar.  It  was  observed  at  the  same 
time  that  all  of  the  alkali  being  used  was  not  recovered  from 
the  tar  and  upon  examination  it  was  found  held  in  a black 
viscous  emulsion  below  the  remaining  hydrocarbon  layer. 

Because  of  the  extreme  viscosity  of  tnis  product,  removal 
of  hydrocarbon  by  use  of  a separatory  funnel  was  impossible. 

To  remove  hydrocarbon,  suction  was  applied  and  from  the  remain- 
ing alkaline  solution  the  acids  were  liberated  by  means  of 
sulphuric  acid.  Having  washed  out  any  potassium  sulphate  re- 
maining, the  acids  were  subjected  to  a combination  of  steam 
and  vacuum  for  drying.  Drying  by  the  usual  process  was  avoided 
because  the  viscosity  of  a.cids  caused  local  superheating  and 


• ' 


* 


- i }tf  , ■ i. 


- 


■ 


■ 


. ...  *'• 


-11- 

resulting  d'-composti  on . To  avoid  this  the  acids  were  warmed 
on  a steam  bath  and  transferred  to  a three  liter  flask  having 
a long  neck.  Dry  steam  was  passed  into  the  war m acids  and 
at  the  same  time  a vacuum  of  600  ram.  was  maintained.  After 
about  300  cc.  of  distillate  had  been  collected  the  steam 
supply  was  shut  off  and  the  vacuum  simultaneously  increased 
to  200  mm.  By  this  method  complete  dehydration  was  accomp- 
lished in  a short  time.  The  small  amount  of  acids  appearing 
in  the  distillate  were  low  boiling.  The  yield  of  acids  thus 
obtained  was  36$. 

A sample  of  the  dried  acid  was  subjected  to  steam  vacuum 
distillation  as  applied  to  the  drying  process  with  the  same 
results,  ie,  any  acid  appearing  in  the  distillate  was  of  the 
lowest  boiling  fraction  and  a yield  of  a few  cc.  per  liter 
of  steam.  This  low  yield  of  acids  which  were  transferred  in  the 
steam  showed  that  the  percent  of  phenol  in  this  sample  of  tar 
was  very  low. 

Extraction  With  Solvents. 

If  the  acids  in  the  tar  are  to  be  separated  and  examined 
as  they  are  in  their  original  form,  these  methods  are  useless. 

By  the  time  a sufficiently  large  yield  could  be  obtained  for 
satisfactory  observation,  the  nature  would  be  so  changed  that 
their  resemblance  to  high  temperature  tan  acids  would  be 
closer. 

Ligroin  and  petroleum  ether  were  tested  out  as  precipit- 
ating agents.  Petroleum  ether  is  more  satisfactory,  there 
being  a heavy  loss  of  all  the  low  melting  solids  in  the 


. 


- 


. 

. 

♦ 


— 1 £— 


ligroin,  whereas,  it  was  from  the  cold  petroleum  ether  solu- 
tion that  these  could  he  obtained  and  resulted  in  giving  the 
nearest  pure  of  any  of  the  extracted  products.  Moreover,  the 
high  boiling  point  of  the  ligroin  made  sufficiently  rapid 
evaporation  by  vacuum  an  impossibility.  In  no  case,  could 
there  be  produced  a coat  of  ice  on  the  outside  of  the  filter 
flask  and  this  was  essential  to  securing  the  last  traces  of 
the  dissolved  solid,  acids* 

The  solvents  tested  for  their  extracting  ability  are  the 
following,  given  in  the  order  of  their  decreasing  power  to 
dissolve  the  acids:  phenol,  sodium  phenolate,  alcoholic  KOH, 

CS2»  CHCI3,  ether,  benzene,  ligroin,  alcohol,  and  petroleum 
ether,  of  which  the  fractional  extraction  solvents  chosen 
were  phenol,  carbon  disulphide,  chloroform,  and  ether. 

A sample  of  the  crude  acids  was  extracted  with  ether  and 
any  undissolved  residue  was  filtered  and  later  treated  success- 
ively with  CHCl^,  CS2»  and  phenol  until  none  remained.  The 
ether  solution  was  poured  slowly  and  with  constant  stirring 
into  about  ten  times  its  volume  of  petroleum  ether  and  a fine- 
ly divided  light  brown  precipitate  formed  which  filtered  readily 
into  a suction  flask  containing  more  petroleum  ether  previous- 
ly cooled  by  rapid  evaporation.  In  the  filter  flask  another 
precipitate  appared  and  this  being  filtered  and  the  filtrate 
as  above  gave  second  precipitate.  This  process  was  followed 
until  no  more  precipitate  could  be  secured  even  by  using  a 
large  excess  of  petroleum  ether  at  zero  degrees,  giving  in 
each  tr  ial  a precipita.te  lighter  in  color  and  more  readily 


- 


-13- 


soluble  in  petroleum  ether  on  warming. 

The  chloroform,  carbon  disulphide,  and  phenol  extracts 
were  likewise  treated  with  petroleum  ether  as  previously,  the 
resulting  precipitation  in  each  case  darker  than  the  preceed- 
ing  and  much  less  soluble  in  the  petroleum  ether. 

Difficulties  in  Extraction  ar  d Precipitation. 

Carbon  disulphide  is  a better  solvent  than  ether,  but 
for  the  separation  of  those  acids  which  are  soluble  in  petrol- 
eum ether  at  room  temperature  and  precipitate  on  cooling,  CSg 
is  a failure.  It  can  not  be  as  readily  evaporated  as  ether 
by  vacuum  and  holds  all  of  the  more  soluble  bodies  in  solution. 

If  the  CS^  extracted  be  poured  rapidly  into  the  petroleum 
ether,  the  very  rapid  precipitation  of  the  solute  occluded 
liquid  acids  resulting  in  a tarry  mass.  This  difficulty  is 
greatly  lessened  if  the  petroleum  ether  is  stirred  rapidly 
and  the  CS£  solution  added  slowly.  This  trouble  is  not  en- 
countered in  the  ca.se  of  the  ether  extract  because  the  sub- 
stances dissolved  by  ether  are  more  readily  soluble  in  petrol- 
eum ether. 

If  a filter  paper  is  used  for  two  or  more  filtrations 
there  appears  a resinous  mass  on  the  paper  which  causes  very 
slow  filtration.  This  is  coused  by  the  high  boiling  acids 
clogging  the  filter  and  then  dissolving  any  solids  to  be 
filtered. 

A purification  of  the  precipitated  acids  was  made  in  the 
same  manner  as  that  previously  done  in  the  extraction  and 


. 


. 


. 


. 


. 


« 


-14- 


this  resulted  in  the  removal  of  all  viscous  liquid  acids 

and  a very  readily  filtration. 

The  residue  that  was  soluble  in  phenol  only,  presented 
difficulties  due  to  the  fact  that  when  the  phenol  solution 
was  poured  into  the  petroleum  ether  it  formed  a viscous  mass 
adhearing  firmly  to  the  walls  of  the  beaker  and  giving  no 
precipitate  in  the  petroleum  ether.  When  a small  amount  of 
ethyl  ether  is  added  to  the  solution,  it  reduces  the  solvent 
action  of  the  phenol,  and  then  a fine  black  precipitate  is 
liberated  which  is  readily  filtered. 

Appearance  of  the  Purified  Products. 

A gradual  darkening  in  color  occurrs  with  the  rise  in 
melting  point  and  decreases  in  solubility  of  the  solid  acids 
separated  by  means  of  organic  solvents.  But  one  slight  var- 
iation occurred  in  this  generalization:  those  solid  acids 

insoluble  in  the  cold  petroleum  ether  solution  and  having  a 
melting  point  between  80-85  degrees  were  more  distinctly 
orange  in  color  than  either  the  preceeding  or  following 
members.  This  characteristic  became  even  more  pronounced 
on  repurifi cation. 

The  lowest  melting  point  of  any  solid  obtained  was 
60  degrees  and  each  succeeding  sample  gave  a rise  of  from 
three  to  five  degrees  until  that  of  six  members  wa,s  taken. 

It  was  in  these  latter  samples  that  the  presence  of  mixtures 
could  be  observed,  by  the  transition  temperature  occurring 


■ 


- 


if . jH 


. 

I m\u  ' 


-15- 


on  application  of  heat.  This  became  more  pronounced  on  using 
those  sa  pies  most  easily  precipitated  in  petroleum  ether. 

The  darker  colored  samples  showed  several  transition  points 
but  no  definite  melting  point.  The  phenol  soluble  extract 
had  a melting  point  of  111  degrees  and  was  the  highest  obtained. 

In  every  case  there  occurred  a decided  change  at  the 
melting  temperature.  The  lightest  colored  products  became 
dark  and  viscous  did  not  return  to  their  former  color  or 
powdered  condition  on  cooling.  At  a few  degrees  above  the 
melting  point  decomposition  set  in  and  the  product  began  to 
increase  in  size. 

After  the  filtration  of  the  acids  the  petroleum  ether  was 
allowed  to  evaporate  and  tne  resulting  precipitate  was  powder- 
ed. All  of  the  lower  melting  solids  were  powdered  with,  con- 
siderable ease  and  had  a tendency  to  adhere  strongly  to  the 
spatula  giving  an  easily  compressed  cake.  Those  having 
higher  melting  points  possessed  this  property  to  a small 
extent  there  being  a considerable  decrease  with  increase  of 
melting  point  and  increase  in  hardness.  The  phenol  soluble 
product  wae  very  compact  and  was  reduced  to  a powder  only 
after  considerable  pressure  had  been  applied. 


. 

* 

. 


■ 


* 


■ 


-16- 

Teste  on  Extracted  Solid  and  Liquid  Acids. 

Numerous  tests  were  applied  to  the  extracted  acids  to 
determine  their  chemical  nature,  among  which  were  solubilities, 
ignition,  combustion,  nitrogen  and  sulphur  determination,  and 
condensation  with  hexame thylene  tetramine. 

The  solvents  used  were  alcohol,  turpentine,  benzene,  ether, 
chloroform,  carbon  disulphide,  phenol  alconolic  KOH,  and 
pyridine . 

All  light  colored  acids  precipitated  by  the  cold  petrol- 
eum ether  were  soluble  to  a greater  or  less  extent  in  all 
solvents.  Turpentine  and  alcohol  showed  the  poorest  solvent 
power. 

The  light  brown  products  were  soluble  in  all  reagents  with 
the  exception  of  turpentine  a no.  alcohol. 

The  darA  products  showed  a decided  decrease  in  solubility 
in  all  solvents.  The  last  extract  was  soluble  in  phenol  and 
alcoholic  KOH  only. 

The  pyridine  test  was  made  that  the  asphaltic  character 
of  the  products  might  be  observed.  Samples  were  dissolved 
in  pyridine  and  some  water  added.  On  being  agitated  a soapy 
foam  was  produced  and  this  remained  for  sometime.  The  addit- 
ion of  K SO4  caused  the  precipitation  of  the  solute. 

The  solubility  tests  in  general  show  that  all  of  the  sub- 
stances are  decidedly  acidic  in  character,  and  that  those 
lightest  in  color  are  more  readily  soluble  in  all  reagents, 
and  also  that  an  increase  in  depth  of  color  is  accompnied  by 


♦ 


♦ 


. 

. 


-17- 


a decrease  in  solubility. 

The  ignition  of  the  liquid  acids  showed  no  characteris- 
tics other  than  that  they  were  of  the  aromatic  type.  Cn 
burning  all  of  the  solid  acids,  however,  there  was  a decided 
change.  Shortly  after  melting  they  began  to  increase  decid- 
edly in  volume  and  charred.  This  volume  assumed  remained 
constant  until  most  of  the  carbon  had  been  burned  off. 

To  obtain  the  percentage  composition,  the  determinations 
of  carbon  hydrogen  and  oxygen  were  made  in  a combustion 
furnace,  nitrogen  was  determined  by  the  Kjeldahl  method, 

ana  sulphur  as  by  the  NagOg  KCIO3  fraction  ation  using 

id  1 • v v (30) 

a Parr  explosion  bomb. 

The  following  gives  the  results  obtained  using  samples 
of  the  lightest  and  darkest  acids: 


TABLE  III 


Color 

of  Samples 

C 

H 

C 

N 

S 

Dark 

(CSg  ext.  ) 

78.6 

4.3 

13.6 

1.5 

1.11 

Light. 

(ether  ext.) 

78.9 

5.4 

13.5 

1.0  2 

1.04 

From  the  data  thus  obtained  there  was  no  indication 
that  these  acids  were  of  very  great  difference  in  molecular 
structure.  Due  to  the  fact,  hov/ever,  that  these  are  decided 
mixtures  an  accurate  determination  is  impossible. 

To  determine  the  position  of  the  hydroxyl  group  in  the 
molecule,  ie,  to  ascertain  if  these  are  either  cargoxylic 

" ' ' — 


- 

■ 


' 


-18- 


acids  or  alcohols,  or  of  true  phenolic  nature,  Redinanol 
condensations  were  made  using  hexamethyline  tetraraine  in 
alcoholic  KOH  solution,  with  the  following  results: 


TABLE  IV 

Sample 

B .P. 

M.P. 

Result 

Residue 

liquid 

• V 

200-10 

light  brown  resin 

none 

liquid 

210-20 

light  brown  resin 

none 

li quid 

220-30 

brown  resin 

none 

li quid 

230- 60 

dark  brown  resin 

none 

liquid 

260-300 

aark  brown  resin 

none 

li quid 

300-340 

black  resin 

light  yellow 

ppt.  in  water 

solid 

65-85 

none 

original 

solid 

94-96 

none 

original 

solid 

104 

none 

original 

crude  tar 

acids 

black  resin 

asphaltic 

powder. 

The 

foregoing 

table  shows 

that  there  are  two 

types  of 

acidic  substances  isolated  by  the  two  methods  used.  Those 
separated  by  distillation  are  of  phenolic  type,  and  may 
contain  a s mall  amount  of  the  lower  melting  solid  acids  which 
precipitate  out  on  condensation  of  the  liquid  acids  and  those 
bearing  decided  acidic  properties  but  not  of  phenolic  type. 

The  residue  left  from  the  crude  tar  acids  after  conden- 


' 


. 


* 


. 


-19- 


sation  was  the  same  in  color  and  character  as  that  obtained 
by  the  extraction  methods.  In  this  way  hexane thy lene  tetra- 

mine  may  be  considered  as  a satisfactory  reagent  for  extract- 
ion of  the  higher  acids. 

Tests  on  Gilsonite. 

Comparative  tests  on  some  asphaltene  extracted  from 
gilsonite  were  made,  with  a view  to  determine  similarity  to 
the  solid  acids  obtained  by  extraction  with  one  exception 
that  there  were  no  low  melting  products  secured,  every  test 
applied  was  identical  in  its  outcome  to  those  applied  to  the 
acids,  leading  to  the  conclusion  that  these  solid  acids  are 
in  reality  asphaltenes.  (No  combustion  on  asphaltenes  from 
gilsonite  was  made). 


- 


. 


- 


-20- 

SUMMARY  OF  INVESTIGATION 

1.  Low  temperature  tar  cannot  be  fractionated  without 

a large  amount  of  decomposition  of  the  higher  boiling  consti- 
tuents giving  a porous  coke  having  a large  volume. 

2.  Subsequent  fractionation  of  the  tar  acids  causes  a 
decrease  in  yields  of  the  higher  boiling  constituents  with 
a corresponding  increase  of  the  low  boiling  fractions. 

3.  No  satisfactory  cutting  temperatures  can  be  select- 
ed for  low  temperature  tar  acids,  as  there  is  no  decided 
increase  in  yield  at  any  one  temperature. 

4.  Tar  acids  may  be  classed  as  to  liquid  and  solids: 
those  soluble  in  common  organic  reagents  and  those  insoluble 
in  all  save  phenol  and  alkali;  those  possessing  the  hydroxyl 
connected  to  the  ring  (truly  phenolic),  and  those  of 
carboxylic  or  alcoholic  natures;  and  those  truly  acidic  and 
asphaltic . 

5.  Free  carbon  determination  in  low  temperature  tar 
cannot  be  made  as  in  high  temperature  because  there  is  found 
in  low  temperature  tar  an  acidic  substance  insoluble  in 
benzene  and  CSg. 

6.  The  asphaltic  bodies  in  low  temperature  tar  decompose 
on  heating  giving  an  increase  in  the  volume. 


1. 

Freeman 

-21- 

BIBLIOGRAPHY 

Petroleum  Times  3 , 543-4. 

2. 

Fischer  and 

Schneider  Ges.  Abhandl.  der  Kenntn.  Kohle. 

3. 

Schneider 

__3,  36-56. 

Ges.  Abhandl.  der.  Kenntn.  Kohle.  2 , 

4. 

Schneider 

133-44. 

Ges.  Abhandl.  der  Kenntn  Kohle.  2.  145-50. 

5. 

Parr  and  Layng  Mining  and  Met.,  1920  Bo.  158  Sect. 4. 

6 . 

Spielman 

Gas  Journal  143,  65. 

. j 

7. 

Lewes 

The  Carbonization  of  Coal  P.192. 

8. 

Loco  Git. 

9. 

Maclaurin 

Gas  Journal  139 , 143 

• 

o 

i — 1 

Lunge 

Coal  Tar  and  Ammonia  1_,  577. 

11. 

Fischer  and 

Schneider  Ges.  Abhandl.  der  -^enntn.  Kohle. 

18. 

Ibid 

3_,  200-12. 

3 .,  1-38. 

13. 

Benson  and 

Canfield  J.  Ind.  Eng.  Chem.  12,  443, 

14. 

Cooper 

By  Product  Coking  P.  138. 

15. 

Lunge  Coal 

Tar  and  Ammonia  1,  219-20. 

15. 

Mulliken 

Identification  of  Pure  Organic  Compounds, 

17. 

Baekland 

_1,  90-106. 

J.  Ind.  Eng.  Chem.  1,  149-61. 

18. 

Redman  and 

Wei  til  J.  Ind  Eng.  Chem.,  6_,  3-15. 

19. 

Baekeland 

J.  Ind  Eng.  Chem.,__5,  506-11. 

20. 

Baekeland 

L.  Ind.  Eng.  Chem.,_l,  545-9. 

21. 

Sage 

J.  Soc . Chem.  Ind.,  ^30,  558. 

22. 

Schne ider 

Brennstoff  Chemie  1 , 70-72,  and  80-85. 

-22- 


23. 

Marcus son 

Z.  Angew.  Chem.,  32,  I 385-6. 

24. 

Hubbard 

Dust  Prevention  Bull.  Dept.  Ag. 

, Ho.  34, 

P.  34. 

25. 

Hubb  ard 

J.  Soc.  Chem.  Ind.  30,  201. 

26. 

Robertson 

Chemistry  of  Coal  P.21. 

27. 

Church 

J.  Ind  Eng.  Chem.,  3 , 227-33* 

28. 

Gluud 

Ges.  Abhandl.  derKenntn.  Kohle. 

,&2  , 236 

56. 

29. 

fischer 

Ges.  Abhandl.  der  Kenntn.  Kohle. 

, 2_, 

22-35. 


-30 


White 


Gas  and  Fuel  Analysis 


P.  206 


